page_title: Groundwater Ambient Monitoring and Assessment Program
hierarchical_section_title: Groundwater Ambient Monitoring and Assessment Program
caption_attribution_description: English: Approximate location of maximum subsidence in the United States identified by research efforts of Dr. Joseph F. Poland (pictured). Signs on pole show approximate altitude of land surface in 1925, 1955, and 1977. The site is in the San Joaquin Valley southwest of Mendota, California. The compaction of unconsolidated aquifer systems that can accompany excessive ground-water pumping is by far the single largest cause of subsidence. The overdraft of such aquifer systems has resulted in permanent subsidence and related ground failures. In aquifer systems that include semiconsolidated silt and clay layers (aquitards) of sufficient aggregate thickness, long-term ground-water-level declines can result in a vast one-time release of “water of compaction” from compacting aquitards, which manifests itself as land subsidence.
context_page_description: The Groundwater Ambient Monitoring and Assessment Program is an all-inclusive monitoring program for groundwater that was implemented in 2000 in California, United States. It was created by the California State Water Resources Control Board as an improvement from groundwater programs that were already in place. GAMA monitors various aspects in groundwater such as the water quality and allotment total through research projects conducted by multiple agencies both statewide and locally sourced. GAMA wants to improve public awareness for groundwater resources as well as improve monitoring on groundwater research across the state to assess potential hazards from this resource.
context_section_description: The Groundwater Ambient Monitoring and Assessment Program (GAMA) is an all-inclusive monitoring program for groundwater that was implemented in 2000 in California, United States. It was created by the California State Water Resources Control Board as an improvement from groundwater programs that were already in place. GAMA monitors various aspects in groundwater such as the water quality and allotment total through research projects conducted by multiple agencies both statewide and locally sourced.  GAMA wants to improve public awareness for groundwater resources as well as improve monitoring on groundwater research across the state to assess potential hazards from this resource.
caption: Land Subsidence in the San Joaquin Valley, CA
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